Localization of potato leafroll virus in leaves of secondarily-infected potato plants

Potato leafroll virus (PLRV) antigen was localized by immunogold labelling in semi-thin leaf sections of secondarily-infected potato plants cv. Bintje. Viral antigen was present in all cell types of the phloem tissue. but occurred most abundantly in the companion cells. Detectable amounts of PLRV antigen were found only in the sieve elements in veins with a large number of infected companion cells. Occasionally, parenchyma cells were also found to be infected. PLRV was not exclusively limited to the phloem tissue in the infected potato plants, but was also found in mesophyll cells neighbouring minor phloem vessles. Spread of virus from cell to cell in the mesophyll was not observed. The distribution of PLRV in the potato leaf tissue has implication on its availability, for acquisition by aphids

Molecular evidence for the occurrence of beet western yellows virus on chickpea in Morocco.

A luteovirus isolate infecting chickpea in Morocco was experimentally transmitted by Myzus persicae to Physalis floridana, on which it produced mild symptoms. When tested in western blots against antisera to known legume luteoviruses, this isolate reacted strongly to beet western yellows virus (BWYV) antiserum, moderately to bean leafroll virus antiserum, while no reaction was recorded with the antiserum against subterranean clover red leaf virus. In PCR, a fragment of ca. 950 bp was amplified, comprising the 3' end of the open reading frame (ORF) 3, the complete coat protein gene (ORF 4), and the non-translated region in between these ORFs. The nucleotide sequence of the amplified fragment showed high similarity with BWYV (approximately 96%), and lower (50–60%) with other luteoviruses reported to infect legumes. On the basis of these data, the Moroccan isolate was identified as BWYV. This is the first molecular evidence for the occurrence of BWYV on chickpea in Morocco, and on food legumes in general in North Africa